A feature of this Vuelta a España has been the reluctance of any of the overall contenders to accept the tag of pre-race favourite, although the majority seem to be happy for Nairo Quintana (Movistar) to carry that burden.

Winner of the Giro d'Italia in May, the Colombian built quietly for this Vuelta at home in Colombia while two of his principal rivals, Alberto Contador and Chris Froome, were crashing out of the Tour de France, and his victory at the Vuelta a Burgos two weeks ago seemed to offer a confirmation of his condition.

On the eve of the Vuelta's first summit finish, however, Quintana looked to downplay expectations that he will instantly look to stamp his authority on the race by attacking on the final haul to Alto Cumbres Verdes, above La Zubia.

"The first mountain-top finish is coming tomorrow, which is my terrain," Quintana said. "I'm getting into the racing pace slowly but steadily, although I think it might be a bit too soon for me to have a crack tomorrow."

Quintana and his stable-mate Alejandro Valverde stole an early march in the overall standings when their Movistar team romped to victory in the opening team time trial in Jerez de la Frontera on Saturday. Since then, Valverde has enjoyed a brief stint in the red jersey and launched a surprise attack on the road to Córdoba on Tuesday with the aim, he said, of "making my rivals nervous."

Quintana, meanwhile, has maintained a low profile, happy to allow Valverde do the majority of the talking to the huddles of reporters outside the team bus. Like many, he admitted that he was feeling the effects of the extreme heat the Vuelta has encountered during its broiling opening days in Andalusia.

"Let's hope the temperature decreases a little tomorrow so we can feel better," Quintana said. "It doesn't really do any good for any of us in the bunch - you body feels different, a bit down."

As if the heat weren't enough of a concern, Quintana and the favourites had to deal with a fraught finale to stage 5 to Ronda when Alberto Contador's Tinkoff-Saxo team fragmented the peloton with a stint of forcing in the crosswinds in the closing 40 kilometres.

Quintana acknowledged that it had been a "stressful" final hour, but Valverde – who famously lost almost ten minutes in similar conditions en route to Saint-Amand-Montrand during last year's Tour – said that he had anticipated the move.

"We were paying attention at the front when we were leaving the town in case there were any splits, and they accelerated. It didn't really surprise us: Tinkoff is a squad that always takes advantage of chances like that, and so it turned out," said Valverde.